1. Field of the Invention
The present invention relates to a musical piece extraction program, a musical piece extraction apparatus, and a musical piece extraction method which can, for example, be suitably applied to a data recording apparatus that records a radio program that is broadcast by a radio broadcasting station (hereinafter referred to as a “radio station”) as program audio data and extracts, from the program audio data, musical piece data of a musical piece broadcast in the radio program.
2. Description of the Related Art
After storing a radio program broadcast by a radio station as program audio data, a related art data processing apparatus acquires from a server a playlist that contains titles (hereinafter referred to as “musical piece titles”) of musical pieces broadcast in the radio program, an artist name(s), and a broadcast start time and broadcast end time of each of the musical pieces broadcast in the radio program such that the musical piece titles, the artist name(s), and the broadcast start times and broadcast end times are associated with one another. Then, the related art data processing apparatus extracts, from the program audio data, musical piece data of a musical piece, referring to the broadcast start time and broadcast end time of the musical piece contained in the playlist (see, for example, Japanese Patent Laid-Open No. 2003-203467 (pages 4 to 6)).
When receiving a radio program as program audio data in a situation where a user has inputted a keyword that indicates a desired musical piece, a related art recording apparatus temporarily stores, in a hard disk, program audio data corresponding to a period of a predetermined length of time (hereinafter referred to as a “holding time length”) ending with the present time such that while the program audio data of the radio program is received, the temporarily stored program audio data is updated all the time as time progresses. In parallel with the temporary storage of the program audio data, the related art recording apparatus acquires, from a radio broadcast information distribution server, “now-on-air information” (which indicates the broadcast start time, musical piece title, artist name, genre name of a musical piece that is currently broadcast in the radio program) periodically, at intervals of a predetermined length (hereinafter referred to as an “acquisition time length”) that is shorter than the holding time length, and determines whether the acquired now-on-air information contains information corresponding to the keyword. If it is determined that the now-on-air information contains the information corresponding to the keyword, the related art recording apparatus extracts, from the program audio data corresponding to a period of the holding time length as temporarily stored in the hard disk, a part of the program audio data that corresponds to a period of the acquisition time length ending with a time point at which the now-on-air information was received. Thereafter, the related art recording apparatus continues to record, on the hard disk, program audio data corresponding to a period from the time point at which the now-on-air information was received onward so as to follow the extracted program audio data, until the now-on-air information periodically acquired ceases to contain the information corresponding to the keyword. In the above-described manner, using the now-on-air information periodically acquired, the related art recording apparatus extracts, from the program audio data of the entire radio program, the musical piece data of a musical piece broadcast in the radio program, and records the extracted musical piece data on the hard disk (see, for example, Japanese Patent Laid-Open No. 2005-332475 (pages 43 to 45)).